The present invention relates to a refractory wear plate assembly for use in a sliding closure unit for controlling the discharge of molten metal from a metallurgical vessel and of the type held in a stationary or adjustable frame and including a refractory base structure having therein a recess and a refractory wear and erosion resistant insert positioned within the recess, the base structure and the insert together defining a planar sliding surface to be abutted with a planar sliding surface of another refractory plate of the sliding closure unit during relative movement therebetween, the insert and the base structure having therethrough a discharge opening, and the insert having a dimension along the sliding surface thereof at least equal to the range of relative movement.
A refractory plate assembly of this general type is disclosed in West German DE-AS No. 27 19 105, wherein the insert is mounted in the base structure and cannot be replaced, at least not with a reasonable degree of effort, since the insert is embedded in the base structure and can be removed therefrom only with great difficulty. Thus, when the insert has become eroded and must be replaced, the entire plate assembly must be replaced, even though the base structure still has utility.
Furthermore, in such known assembly, particular dimensional tolerances must be maintained between the high value insert and the base structure. If such dimensional tolerances are too close or tight, then thermal stresses eventually will create cracks in the base structure and in the insert during use of the assembly. On the other hand, if the dimensional tolerances between the two elements of the assembly are too great, there inevitably will occur intolerable displacements of the insert relative to the base structure during operation.